The invention relates to a wall cleaning valve structure, more particularly, for cleaning a wall by means of a gas or vapor under pressure. Such walls may be, for example, container walls which have been dirtied by anything held in the container, such as liquid remainders, for example, mineral oils or the like. The walls may be coated with dust or granular material or any other bulk type materials. For example, the inner surfaces of the walls of a bag emptying machine require cleaning from time to time. This also applies to the walls for any other equipment arranged for cooperation with the bag emptying machine, for example, dosing equipment for pigment materials in the paint industry or the like. Such cleaning may also be necessary in food processing machines especially where the food substances have a tendency to adhere to the walls of the handling equipment. The present valve structure extends through the wall to be cleaned and is normally permanently installed in the wall to be cleaned.
It is well known to clean the surface of equipment by means of a jet of a pressurized gas, for example, air or steam. Especially cleaning by means of steam or pressurized steam is employed for removing remainder layers formed by thermoplastic substances produced from mineral oils.
Cleaning devices used heretofore are either stationary or mobile. The respective jets of cleaning medium are either movable or also stationary. It is also known to employ mobile equipment normally having a long handle to one end of which a jet nozzle is attached. In this connection it should be noted that in addition to the air and steam jet devices certain cleaning jobs are performed by blasting solid particles onto the surface to be cleaned, for example, by special sandblasting equipment. Such solid particle blasting equipment may also be combined with the ejection of air or steam under pressure.
However, even the mobile equipment with fairly long handles is not always entirely satisfactory, for example, for cleaning the inner surfaces of equipment housings and material containers of all kinds. For instance, the components to be cleaned may be exposed alternately to materials of different kinds such as different pigments or the like. Even the mobile equipment cannot reach all areas to be cleaned by a cleaning medium depending on the size and shape of the housing or container. This lack of accessibility applies particularly to the housing of bag emptying machines. Such machines are used for opening bags containing soot, pigments, cement, synthetic materials and so forth and it is necessary that the bags are being opened substantially without any dust formation. In addition, the bags must be opened without any manual assistance and the bulk material removed from the bags must be transported separately from the empty bags. These requirements call for housing structures which are not easily accessible for cleaning purposes.
It is frequently required by the purchaser of such equipment that at least a light cleaning job may be accomplished when the machinery is to be changed from one type of material to another, for example, from pigment of one color to a pigment of another color so as to remove the material from the wall surfaces prior to the change over to handling another material. Stated differently, it is frequently necessary that a contamination of the new material to be handled by remainders of the old material is avoided with certainty without the creation of a dust or odor nuisance for the operating personnel or in the shop or factory space.
The stationary installation of directed jet nozzles may provide a certain improvement with regard to the accessibility of all surface areas, especially in machinery of the above kind. However, prior art stationary installations are not completely satisfactory. Normally, the rinsing or cleaning medium impinges on the surface to be cleaned at right angles in the form of a full jet or in the form of a tapered hollow cone, whereby the kinetic engergy of the jet becomes effective only on a relatively limited surface area. Thus, the cleaning efficiency is limited to the impinging zone and the kinetic energy of the jet is at least partially used up by the rebound of the cleaning medium.